Effect of follicular cells on calcitonin gene expression in thyroid parafollicular cells in cell culture

Neuroendocrine Factors in Melanoma Pathogenesis

Simple Summary

Melanoma is a very aggressive and fatal malignant tumor. While curable if diagnosed in its early stages, advanced melanoma, despite the complex therapeutic approaches, is associated with one of the highest mortality rates. Hence, more and more studies have focused on mechanisms that may contribute to melanoma development and progression. Various studies suggest a role played by neuroendocrine factors which can act directly on tumor cells, modulating their proliferation and metastasis capability, or indirectly through immune or inflammatory processes that impact disease progression. However, there are still multiple areas to explore and numerous unknown features to uncover. A detailed exploration of the mechanisms by which neuroendocrine factors can influence the clinical course of the disease could open up new areas of biomedical research and may lead to the development of new therapeutic approaches in melanoma.

Abstract

Melanoma is one of the most aggressive skin cancers with a sharp rise in incidence in the last decades, especially in young people. Recognized as a significant public health issue, melanoma is studied with increasing interest as new discoveries in molecular signaling and receptor modulation unlock innovative treatment options. Stress exposure is recognized as an important component in the immune-inflammatory interplay that can alter the progression of melanoma by regulating the release of neuroendocrine factors. Various neurotransmitters, such as catecholamines, glutamate, serotonin, or cannabinoids have also been assessed in experimental studies for their involvement in the biology of melanoma. Alpha-MSH and other neurohormones, as well as neuropeptides including substance P, CGRP, enkephalin, beta-endorphin, and even cellular and molecular agents (mast cells and nitric oxide, respectively), have all been implicated as potential factors in the development, growth, invasion, and dissemination of melanoma in a variety of in vitro and in vivo studies. In this review, we provide an overview of current evidence regarding the intricate effects of neuroendocrine factors in melanoma, including data reported in recent clinical trials, exploring the mechanisms involved, signaling pathways, and the recorded range of effects.

Phaeochromocytomas and paragangliomas: A difference in disease behaviour and clinical outcomes

BACKGROUND

Phaeochromocytomas and paragangliomas arise from the same chromaffin cell, but evidence suggests they do not represent a single clinical entity. The aim of this study was to compare clinical presentations, outcomes of surgical and oncological treatments and survival in patients with phaeochromocytomas and paragangliomas.

METHODS

A retrospective review was undertaken of all patients treated for these conditions at our centre between 1983 and 2012.

RESULTS

One hundred and six patients (88 adults, 18 children) with phaeochromocytoma (n = 83) or paraganglioma (n = 23) were studied. Catecholamine symptoms and incidentalomas were the main presentations in phaeochromocytoma patients (67% and 17%) respectively, but in those with paragangliomas pain (39%) was more common (P < 0.001). More paragangliomas were malignant (14/23 vs 9/83, P < 0.0001), larger (9.17 ± 4.95 cm vs. 5.8 ± 3.44 cm, P = 0.001) and had a higher rate of conversion to open surgery (P = <0.01), more R2 resections, more postoperative complications and a longer hospital stay (P = 0.014). MIBG uptake in malignant paragangliomas was lower than in malignant phaeochromocytomas (36% vs. 100%, P = 0.002) and disease stabilisation was achieved in 29% and 86% of patients respectively. (90) Y-DOTA-octreotate had a 78% response rate in malignant paragangliomas.

CONCLUSION

The clinical differences between paragangliomas and phaeochromocytomas support the view that they should be considered as separate clinical entities.

Crinophagy in Thyroid Follicular and Parafollicular Cells of Male Obese Zucker Rat

Comparison between lean (Fa/?) and obese (fa/fa) young adult male Zucker rat thyroids reveals that obese rats display larger clusters of parafollicular cells than the lean ones with a lesser blood supply. Fa/? thyroid typically shows single or "twin" C cells in follicles; fa/fa parafollicular cells appear with three functional aspects. Crinophagy is found in the fa/fa C cells amassing numerous aberrant calcitonin-containing vesicles among which lysosomes build these autophagic bodies by capturing vesicle contents, other organelles and, fusing with each other, increase their size. Other C cells contain many secretory vesicles but show few or no crinophagic structures. Another parafollicular cell type is revealed with scant organelles and highly contrasted secretory vesicles, different from calcitonin. Hypercalcemia of fa/fa rats corresponds to increased C cells population with accrued calcitonin production but a low calcitonin plasma level - verified by others - is likely caused by crinophagy of the altered vesicles. In addition, the T thyrocytes of fa/fa rats exhibit crinophagy bodies; this can confirm their hypothyroidism. Possibly, the known leptin mutation along with other unknown paracrine secretions alter both T and C thyrocytes' functions of the fa/fa rats, allowing high intracellular calcium and lower pH favoring autophagocytosis. Other longitudinal, interdisciplinary studies should further clarify the complex paracrine interactions existing between these endocrine structures because this animal model could be useful to understand human defects, such as the metabolic syndrome that involves obesity, cardiovascular, renal, hepatic, non-insulin dependent diabetes mellitus (NIDDM), hypothyroidism defects, as well as the etiology of thyroid medullary tumors.

Clinical risk factors for malignancy and overall survival in patients with pheochromocytomas and sympathetic paragangliomas: primary tumor size and primary tumor location as prognostic indicators

CONTEXT

Pheochromocytomas and sympathetic paragangliomas are rare neuroendocrine tumors for which no precise histological or molecular markers have been identified to differentiate benign from malignant tumors.

OBJECTIVE

The aim was to determine whether primary tumor location and size are associated with malignancy and decreased survival.

DESIGN AND SETTING

We performed a retrospective chart review of patients with either pheochromocytoma or sympathetic paraganglioma.

PATIENTS

The study group comprised 371 patients.

MAIN OUTCOME MEASURES

Overall survival and disease-specific survival were analyzed according to tumor size and location.

RESULTS

Sixty percent of patients with sympathetic paragangliomas and 25% of patients with pheochromocytomas had metastatic disease. Metastasis was more commonly associated with primary tumors located in the mediastinum (69%) and the infradiaphragmatic paraaortic area, including the organ of Zuckerkandl (66%). The primary tumor was larger in patients with metastases than in patients without metastatic disease (P < 0.0001). Patients with sympathetic paragangliomas had a shorter overall survival than patients with pheochromocytomas (P < 0.0001); increased tumor size was associated with shorter overall survival (P < 0.001). Patients with sympathetic paragangliomas were twice as likely to die of disease than patients with pheochromocytomas (hazard ratio = 1.93; 95% confidence interval = 1.20-3.12; P = 0.007). As per multivariate analysis, the location of the primary tumor was a stronger predictor of metastases than was the size of the primary tumor.

CONCLUSIONS

The size and location of the primary tumor were significant clinical risk factors for metastasis and decreased overall survival duration. These findings delineate the follow-up and treatment for these tumors.

A new organotypic culture of thyroid tissue maintains three-dimensional follicles with C cells for a long term

Thyroid follicles embedded in extracellular matrix (ECM) seem to be supplied enough oxygen by a dense network of capillaries in vivo. Air exposure (AE) causes cells to increase oxygen availability in vitro. We speculated that three-dimensional (3D) environment of ECM together with AE may be applied to a thyroid tissue-organotypic culture, simply simulating such a microenvironment of follicles. To address the issue, we performed 3D collagen gel culture of minced thyroid tissues with or without AE. Most follicles in the tissues without AE died within 7 days. In culture with AE, most of the follicles with calcitonin-positive C cells were kept for over one month. Immunohistochemistry showed that thyrocytes displayed thyroglobulin, thyrotropin receptor, thyroid transcription factor-1 (TTF-1), and pendrin, which are all crucial for thyroid function. C cells expressed calcitonin gene-related peptide and TTF-1. Our study is the first demonstration that 3D collagen gel culture with AE retains 3D thyroid follicles with C cells for a long term. This suggests that ECM and oxygen supply together may be crucial for maintenance of 3D follicle structure and function. Our method will possibly open a new path to the study of thyrocyte-C cell interaction and thyroid biology.